JP6044718B2 - Grinder - Google Patents

Description

The present invention relates to a grinder to which a rotary tool is attached.

The grinder includes a spindle that is rotationally driven, and various rotary tools are attached to the spindle according to the purpose and application. For example, a disc-shaped grindstone, a brush, a cutter, or the like is attached to the spindle of the grinder. The grindstone attached to the spindle of the grinder includes a grinding grindstone and a cutting grindstone. Brushes attached to the grinder spindle include wire brushes and wireless brushes. The cutter attached to the spindle of the grinder includes a diamond cutter. In the following description, various rotary tools attached to the spindle may be collectively referred to as “wheels”.

The grinder as described above is required to be equipped with a wheel guard that covers more than half of the outer periphery of the wheel. Moreover, when using a grinder, it is necessary to change the installation position of the wheel guard according to the purpose and application.

Therefore, Patent Document 1 describes a grinder that can change the mounting position of the wheel guard without using a tool such as a spanner or a screwdriver. In the grinder described in Patent Document 1, a wheel guard is rotatably attached to the packing land. The packing land is provided with a holding groove, and the foil guard set ring is provided with a rib that fits into the holding groove. In addition, a coil spring is disposed between the packing land and the set ring to prevent the rib fitted in the holding groove from dropping off.

In the grinder described in Patent Document 1 having the above structure, when the wheel guard is pushed upward in the axial direction of the spindle against the bias of the coil spring, the fitting between the holding groove and the rib is released. That is, the fixing of the wheel guard is released, and the mounting position of the wheel guard can be changed. Thereafter, when the push-up with respect to the wheel guard is released, the rib is again fitted into the holding groove by the bias of the coil spring. That is, the wheel guard is fixed at a new mounting position.

Japanese Utility Model Publication No. 6-36764

In the grinder described in Patent Document 1, when the wheel guard is pushed upward in the axial direction of the spindle, the fixing of the wheel guard is released. Here, the wheel attached to the grinder is often held substantially parallel to the surface of an object such as stone, concrete, and wood and pressed against the surface of the object. At this time, when the foil guard comes into contact with the object surface for some reason, an upward force in the axial direction of the spindle is applied to the foil guard. In other words, a force acting to release the fixing of the wheel guard is applied to the wheel guard. Therefore, there is a possibility that the fixing of the wheel guard may be released against the intention of the worker using the grinder.

An object of the present invention is to reduce as much as possible the possibility that the fixing of the wheel guard is released against the operator's intention.

Grinder of the present invention includes a spindle rotating tool is mounted, and the wheel guard for covering the rotating tool mounted on the spindle, provided on the body for rotatably holding the spindle, a mounting pedestal which surrounds the spindle, provided in the wheel guard, wherein the includes a fitting portion fitted to the mounting base, and the mounting base and the concave portion is provided on one of the fitting portion, the mounting base and the fitting portion The other is provided with a convex portion, and when the concave portion and the convex portion are fitted, rotation of the wheel guard in the circumferential direction of the spindle is restricted, and the wheel guard displacement in the radial direction of the spindle, the allowed within the clearance provided between the mounting base and the fitting portion, in the radial direction of the wheel guard said spindle Once position, engagement between the concave portion and the convex portion is released, the wheel guard is rotatable in the circumferential direction of the spindle.

In one aspect of the present invention, the between the mounting base and the fitting portion is provided elastic body, the elastic body, the wheel guard so that said mounting boss and the said fitting portion is fitted exert a biasing force to said the wheel guard is displaced in the radial direction of the spindle against the biasing force of the elastic body, the fitting between the concave and the convex portion is released, the wheel guard the It can be rotated in the circumferential direction of the spindle.

In another aspect of the present invention, the fitting portion has a cylindrical shape that fits on the outer periphery of the mounting portion base, the concave portion is provided on the outer peripheral surface of the mounting base, and the convex portion is the fitting portion. Provided on the inner peripheral surface of the joint portion, the elastic body is provided on the inner peripheral surface of the fitting portion and at a position facing the convex portion.

In another aspect of the invention, the elastic body is a leaf spring that curves toward the inside of the fitting portion.

In another aspect of the present invention, the main body includes a housing that houses a drive source of the spindle, and a gear case that rotatably holds the spindle. The mounting base is integrally formed with a lid member that closes the opening of the gear case.

In another aspect of the present invention, a protruding portion that protrudes inward from the inner peripheral surface of the fitting portion, an engaging portion that protrudes outward from the outer peripheral surface of the mounting base, and engages with the protruding portion, Is provided.

In another aspect of the present invention, the engaging portion is provided in a region other than a region where the concave portion is provided in the mounting base.

In another aspect of the present invention, the grinder is a grinder having a spindle on which a rotating tool is mounted, a wheel guard that covers the rotating tool, and a mounting base to which the wheel guard is attached. A fitting portion that can be fitted to the mounting base is integrally formed, and a clearance is provided between the fitting portion and the mounting base in the radial direction of the spindle, and the wheel guard is attached to the mounting base. It is movable in the radial direction within the clearance range with respect to the pedestal, and the fitting portion and the mounting base are fitted by moving the wheel guard in the radial direction within the clearance range. Between the fixed state in which the wheel guard is engaged and the pivotable state in which the wheel guard is not fitted can be switched. Rotation of Dollar circumferential direction is fixed in the rotatable state, the wheel guard is rotatable in the circumferential direction of the spindle.

In another aspect of the present invention includes a recess provided in one of said fitting portion and the mounting base, and a protrusion provided to the other of said mounting pedestal and the fitting portion The concave portion and the convex portion are fitted in the fixed state.

In another aspect of the present invention, an elastic body is provided for fitting the concave portion and the convex portion in the radial direction of the spindle .

According to the present invention, it is possible to reduce the possibility that the fixing of the wheel guard is released against the operator's intention.

It is sectional drawing which shows the structure of the grinder to which this invention was applied. (A) is a bottom view of the packing land, (b) is a side view, and (c) is a cross-sectional view along the line AA shown in (b). (A) is a bottom view of a foil guard, (b) is a side view, and (c) is a cross-sectional view along the line BB shown in (b). (A) is a side view which shows the attachment procedure of a wheel guard, (b) is sectional drawing which shows the fitting state of a mounting base and a fitting part. (A)-(d) is explanatory drawing which shows the procedure which changes the attachment position of a wheel guard.

Hereinafter, an example of a grinder to which the present invention is applied will be described in detail with reference to the drawings. As shown in FIG. 1, the grinder 1 according to the present embodiment includes a diamond grinding wheel (hereinafter referred to as “grinding wheel 2”) as a rotating tool, and flattens the surface of concrete, stone, or the like. Used for grinding work.

The grinder 1 includes a main body 5 including a housing 3 and a gear case 4. The housing 3 has a substantially cylindrical shape as a whole, and an electric motor 6 as a drive source is accommodated in the housing 3. The electric motor 6 is connected to a commercial power source via a power cord 7 drawn from the rear end of the housing 3.

The gear case 4 includes a case main body 10 and a packing land 11 as a lid member that closes an opening of the case main body 10, and is attached to the front end of the housing 3. Two bearings (needle bearing 12 and ball bearing 13) are provided inside the gear case 4, and a spindle (output shaft) 20 is rotatably held by these bearings. The spindle 20 is orthogonal to the output shaft 6 a of the electric motor 6, and one end of the spindle 20 protrudes outside through the packing land 11. On the other hand, a bevel gear 22 that meshes with a bevel gear 21 attached to the output shaft 6 a of the electric motor 6 is attached to the other end of the spindle 20 located in the gear case 4. The rotation of the electric motor 6 is converted to 90 degrees by the bevel gear pair, and the rotation speed is reduced and transmitted to the spindle 20. That is, the spindle 20 is rotationally driven by the electric motor 6.

The grindstone wheel 2 includes a substrate 2a made of a disk-shaped steel plate, and a plurality of diamond grindstones are fixed to the surface of the substrate 2a by bonding or other means. In addition, a mounting hole into which the spindle 20 is inserted is provided at the center of the substrate 2a, and the grindstone wheel 2 is mounted on the spindle 20 that passes through the mounting hole. Specifically, the grindstone wheel 2 is fixed to the spindle 20 by a wheel washer and a lock nut, and rotates integrally with the spindle 20. The housing 3 is provided with a switch (not shown). When this switch is operated, electric power is supplied to the electric motor 6 and the output shaft 6a of the electric motor 6 rotates. Then, the spindle 20 connected to the output shaft 6a via the bevel gear pair rotates, and the grindstone wheel 2 fixed to the spindle 20 rotates.

A wheel guard 30 is attached to the gear case 4 so as to cover at least 1/2 of the outer periphery of the grinding wheel 2. Hereinafter, the attachment structure of the wheel guard 30 will be described in detail.

As shown in FIGS. 2A and 2C, a through hole 40 through which the spindle 20 (FIG. 1) passes is provided at the center of the packing land 11. As shown in FIGS. 2A to 2C, a cylindrical mounting base 41 is integrally formed on the lower surface of the packing land 11. The mounting base 41 is formed around the through hole 40 so as to surround the through hole 40. The mounting base 41 extends downward along the axis of the through hole 40. In other words, the mounting base 41 is formed in an annular shape, and the axis of the mounting base 41 coincides with the axis of the through hole 40. That is, the mounting base 41 surrounds the spindle 20 (FIG. 1) protruding from the through hole 40.

On the outer peripheral surface of the mounting base 41, a plurality of concave portions 42 are provided at regular intervals along the circumferential direction. Specifically, as shown in FIGS. 2A and 2C, eight concave portions 42 are formed over about a half circumference of the outer peripheral surface of the mounting base 41. On the other hand, an escape portion 43 is formed on the outer peripheral surface of the mounting base 41 and in a region where the concave portion 42 is not formed. The escape portion 43 is recessed toward the inside of the mounting base 41, and the bottom surface of the escape portion 43 is flat. As shown in FIGS. 2A and 2C, the eight recesses 42 include a recess 42 a that faces the escape portion 43 across the center of the through hole 40. That is, the escape portion 43 and the concave portion 42a are arranged at positions different by 180 degrees and face each other. Further, as shown in FIG. 2B, the end of the mounting base 41 (on the side of the grinding wheel) that protrudes outward from the outer peripheral surface of the mounting base 41 in the region where the recess 42 is not provided. An engaging portion 41a that engages with a protruding portion 35 (FIG. 3) of the fitting portion 32 described later is provided. That is, the engaging portion 41a is provided on the mounting base 41 in a region other than the region where the concave portion 42 is provided.

As shown in FIG. 1, the foil guard 30 has a cover portion that includes a horizontal portion 30 a extending in the radial direction of the spindle 20 and a vertical portion 30 b extending from the edge of the horizontal portion 30 a in the axial direction of the spindle 20. In a plan view, it has a substantially fan shape (FIG. 3A). In other words, the horizontal portion 30 a of the wheel guard 30 is parallel to the rotation plane of the grinding wheel 2. On the other hand, the vertical portion 30 b of the wheel guard 30 is perpendicular to the rotation plane of the grinding wheel 2 and covers the radially outer side of the grinding wheel 2.

As shown in FIG. 3A, a substantially circular opening 31 is formed in the horizontal portion 30 a of the wheel guard 30. Further, as shown in FIG. 3B, a cylindrical fitting portion 32 extending upward from the edge of the opening 31 along the axis of the opening 31 is integrally formed on the upper surface of the horizontal portion 30a. ing. The separate horizontal portion 30a and the fitting portion 32 may be integrated by welding or the like.

As shown in FIGS. 3A and 3C, a convex portion 33 is provided on the inner peripheral surface of the fitting portion 32. A leaf spring 34 as an elastic body is provided on the inner peripheral surface of the fitting portion 32 and at a position facing the convex portion 33. That is, the convex part 33 and the leaf | plate spring 34 are arrange | positioned in the position which differs 180 degree | times, and are mutually opposing. In other words, the convex part 33 and the leaf | plate spring 34 are arrange | positioned in the symmetrical position with respect to the spindle 20 shown by FIG. The leaf spring 34 is curved toward the inside of the fitting portion 32. Specifically, both ends of the leaf spring 34 are fixed to the inner peripheral surface of the fitting portion 32, while the center of the leaf spring 34 projects toward the center of the fitting portion 32. In other words, the leaf spring 34 is curved so that the center in the longitudinal direction is closest to the convex portion 33. Furthermore, a pair of projecting portions 35 projecting inward from the inner peripheral surface is provided on the inner peripheral surface of the fitting portion 32. The protruding amount of the protruding portion 35 toward the radially inner side of the fitting portion 32 is smaller than the protruding amount of the protruding portion 33. The protrusion 35 and the engaging portion 41a (FIG. 2B) of the mounting base 41 are engaged in the vertical direction, so that the wheel guard 30 is prevented from falling off the mounting base 41. Further, the leaf spring 34 and the convex portion 33 are also engaged with the engaging portion 41a in the vertical direction, so that the foil guard 30 can be more reliably prevented from falling off the mounting base 41.

As shown in FIG. 4A, the wheel guard 30 is attached to the packing land 11 from below the packing land 11. In other words, the mounting base 41 extending downward from the lower surface of the packing land 11 is fitted inside the fitting portion 32 extending upward from the upper surface of the wheel guard 30.

As shown in FIG. 4B, when the mounting base 41 is fitted into the fitting portion 32, the position of the relief portion 43 provided on the mounting base 41 and the fitting portion 32 are provided. The position of the leaf spring 34 is adjusted. When the escape portion 43 and the leaf spring 34 are aligned, the position of the concave portion 42a facing the relief portion 43 and the position of the convex portion 33 facing the leaf spring 34 automatically match. It is obvious that when the concave portion 42a and the convex portion 33 are aligned, the position of the escape portion 43 and the position of the leaf spring 34 automatically match. In any case, when the mounting base 41 is fitted into the fitting portion 32, the leaf spring 34 provided on the inner peripheral surface of the fitting portion 32 is as shown in FIG. It is arranged between the inner peripheral surface of the fitting part 32 and the outer peripheral surface of the mounting base 41. More specifically, the leaf spring 34 is disposed between the inner peripheral surface of the fitting portion 32 and the bottom surface of the escape portion 43.

Thereafter, when the fitting portion 32 (foil guard 30) shown in FIG. 4B is rotated counterclockwise, the leaf spring 34 is moved into the fitting portion 32 as shown in FIG. The gap between the peripheral surface and the bottom surface of the escape portion 43 is pushed into the gap between the inner peripheral surface of the fitting portion 32 and the outer peripheral surface of the mounting base 41 to bend. Then, the wheel guard 30 is displaced (moved) from the fitting portion side shown in FIG. 3B to the vertical portion side by the elastic restoring force of the bent leaf spring 34. As a result, as shown in FIG. 5A, the convex portion 33 at a position different by 180 degrees with respect to the leaf spring 34 is attracted to the opposing concave portion 42 and fitted into the concave portion 42. That is, the mounting base 41 (concave portion 42) and the fitting portion 32 (convex portion 33) are fitted by the urging of the leaf spring 34, and the wheel guard 30 is fixed.

The position of the wheel guard 30 shown in FIG. 5A is changed as follows. First, the wheel guard 30 is pushed (or pulled), and the wheel guard 30 is displaced in the radial direction (arrow direction) of the through-hole 40 against the bias of the leaf spring 34. In other words, the leaf spring 34 is bent, and the wheel guard 30 is displaced (moved) from the vertical portion side shown in FIG. 3B to the fitting portion side. Then, as shown in FIG. 5B, the convex portion 33 is detached from the concave portion 42. That is, the fitting between the mounting base 41 (concave portion 42) and the fitting portion 32 (convex portion 33) is released, and the fixing of the wheel guard 30 is released. In addition, it is clear from the above description and drawings that the radial direction of the through hole 40 shown in FIG. 5A and the radial direction of the spindle 20 shown in FIG. That is, when the wheel guard 30 is displaced in the radial direction of the spindle 20 against the urging of the leaf spring 34, the fitting between the concave portion 42 and the convex portion 33 is released, and the fixing of the wheel guard 30 is released. That is, the wheel guard 30 can be rotated in the circumferential direction of the spindle 20.

Next, the wheel guard 30 is rotated by a desired angle in the direction of the arrow shown in FIG. 5B while maintaining the pushing (or pulling) on the wheel guard 30. For example, as shown in FIGS. 5B and 5C, the wheel guard 30 is rotated by one recess.

Thereafter, when the pushing (or pulling) on the wheel guard 30 is released, as shown in FIG. 5D, the convex portion 33 is fitted into the new concave portion 42 by the urging of the leaf spring 34, and the foil guard 30 is moved. It will be fixed again. In order to displace the wheel guard 30 as described above, a clearance is required between the inner peripheral surface of the fitting portion 32 and the outer peripheral surface of the mounting base 41. Specifically, when the wheel guard 30 is displaced in the radial direction of the spindle 20, the convex portion 33 is also displaced (moved) in the same direction by the same distance. And in order to make the convex part 33 fitted to the concave part 42 detach | leave from the concave part 42, the moving distance of the convex part 33 needs to exceed the fitting length. Therefore, a clearance necessary to ensure a moving distance exceeding the fitting length is provided between the inner peripheral surface of the fitting portion 32 and the outer peripheral surface of the mounting base 41. In the present embodiment, the clearance is ensured by making the cross-sectional shape of the fitting portion 32 substantially elliptical.

In this embodiment, when the wheel guard 30 shown in FIG. 1 is displaced in the radial direction of the spindle 20, the concave portion 42 (FIG. 2) provided in the packing land 11 and the convex portion 33 provided in the foil guard 30. The engagement with (FIG. 3) is released, and the fixing of the wheel guard 30 is released. In other words, even if an axially upward force or an axially downward force of the spindle 20 is applied to the wheel guard 30, the fitting between the concave portion 42 and the convex portion 33 is not released, and the fixing of the foil guard 30 is also possible. It will not be released. Therefore, the possibility that the fixing of the wheel guard 30 is released against the intention of the worker who uses the grinder 1 is extremely low. Further, when the grinding wheel 2 shown in FIG. 1 is broken during rotation, in many cases, the fragments of the grinding wheel 2 collide with the inner surface of the vertical portion 30 b of the wheel guard 30. At this time, a radially outward force of the spindle 20 is applied to the wheel guard 30. In other words, a force that acts to release the fixing of the wheel guard 30 is applied to the wheel guard 30.

However, as shown in FIGS. 3A and 3C, the convex portion 33 is disposed on the opposite side of the vertical portion 30b with the center of the fitting portion 32 interposed therebetween. Therefore, the convex part 33 does not separate from the concave part 42 (FIG. 2) due to the force applied to the wheel guard 30 when the fragments of the grinding wheel 2 collide with the inner surface of the vertical part. In other words, the force applied to the wheel guard 30 when the fragments of the grinding wheel 2 collide with the inner surface of the vertical portion may act to strengthen the fitting between the concave portion 42 and the convex portion 33, but the concave portion 42. It does not act so as to release the fitting between the projection 33 and the projection 33. Further, only the wheel guard 30 needs to be operated to release the wheel guard 30 from being fixed. Therefore, the number of parts is reduced as compared with a case where a release button for releasing the fixation of the wheel guard 30 is provided. In addition, the wheel guard 30 can be easily released even with the work gloves on, and the operability is good. Furthermore, when working with the main body 5 pressed against the grinding wheel 2 side, the possibility that the wheel guard 30 is released is extremely low.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, the leaf spring 34 as an elastic body can be replaced with a coil spring or rubber. Moreover, the convex part 33 should just be provided in any one of the attachment base 41 and the fitting part 32, and the recessed part 42 should just be provided in any one of the attachment base 41 and the fitting part 32. FIG. That is, the convex portion 33 can be provided on the mounting base 41 and the concave portion 42 can be provided on the fitting portion 32. Moreover, the convex part 33 should just be provided in any one of the foil guard 30 and the attachment base 41, and the recessed part 42 should just be provided in any one of the wheel guard 30 and the attachment base 41. Furthermore, the number and arrangement of the concave portions 42 and the convex portions 33 can be appropriately changed as necessary.

DESCRIPTION OF SYMBOLS 1 Grinder 2 Grinding wheel 2a Board | substrate 3 Housing 4 Gear case 5 Main body 6 Electric motor 6a Output shaft 7 Power cord 10 Case main body 11 Packing land 12 Needle bearing 13 Ball bearing 20 Spindle 21 Bevel gear 22 Bevel gear 30 Wheel guard 30a Horizontal part 30b Vertical part 31 Opening portion 32 Fitting portion 33 Protruding portion 34 Leaf spring 35 Protruding portion 40 Through hole 41 Mounting base 41a Engaging portion 42, 42a Recessed portion 43 Escape portion

Claims (10)

A spindle on which a rotating tool is mounted;
A wheel guard covering the rotary tool mounted on the spindle ;
A mounting base provided on a main body for rotatably holding the spindle, and surrounding the spindle;
Provided in the wheel guard, it has a fitting portion fitted to the mounting base,
A concave portion is provided in one of the mounting base and the fitting portion ,
A convex portion is provided on either one of the mounting base and the fitting portion ,
When the concave portion and the convex portion are fitted, rotation of the wheel guard in the circumferential direction of the spindle is restricted, and displacement of the wheel guard in the radial direction of the spindle is controlled by the mounting base. And within the range of the clearance provided between the fitting portion and
When the wheel guard is displaced in the radial direction of the spindle, the fitting between the concave portion and the convex portion is released, and the wheel guard can be rotated in the circumferential direction of the spindle. Elastic member is provided between said mounting base and the fitting portion,
The elastic body exerts a biasing force on the foil guard so that the mounting base and the fitting portion are fitted,
When the wheel guard is displaced in the radial direction of the spindle against the urging force of the elastic body, the fitting between the concave portion and the convex portion is released, and the wheel guard rotates in the circumferential direction of the spindle. The grinder of claim 1, wherein the grinder is movable. The fitting portion has a cylindrical shape that fits on the outer periphery of the mounting base,
The concave portion is provided on an outer peripheral surface of the mounting base, the convex portion is provided on an inner peripheral surface of the fitting portion, and the elastic body is on the inner peripheral surface of the fitting portion, The grinder of Claim 2 provided in the position facing the said convex part.   The grinder of Claim 3 whose said elastic body is a leaf | plate spring which curves toward the inner side of the said fitting part. The main body includes a housing that houses a drive source of the spindle, and a gear case that rotatably holds the spindle,
The grinder according to any one of claims 1 to 4, wherein the mounting base is integrally formed with a lid member that closes an opening of the gear case. A projecting portion projecting inward from the inner peripheral surface of the fitting portion;
The grinder according to any one of claims 1 to 5, further comprising an engaging portion that protrudes outward from an outer peripheral surface of the mounting base and engages with the protruding portion. The recess is provided in the mounting base;
The grinder according to claim 6, wherein the engagement portion is provided in a region of the mounting base other than a region where the concave portion is provided. A spindle on which a rotating tool is mounted;
A wheel guard covering the rotating tool;
A grinder having a mounting base to which the wheel guard is attached,
The foil guard is integrally formed with a fitting portion that can be fitted to the mounting base.
In the radial direction of the spindle, a clearance is provided between the fitting portion and the mounting base,
The wheel guard is movable with respect to the mounting base in the radial direction within the clearance.
By moving the wheel guard in the radial direction within the range of the clearance, switching is performed between a fixed state in which the fitting portion and the mounting base are fitted and a rotatable state in which the fitting guard is not fitted. Is possible,
In the fixed state, the rotation of the wheel guard in the circumferential direction is fixed,
A grinder , wherein the wheel guard is rotatable in the circumferential direction of the spindle in the rotatable state . A recess provided in one of the fitting portion and the mounting base;
A convex portion provided on the other of the fitting portion and the mounting base,
The grinder according to claim 8 , wherein the concave portion and the convex portion are fitted in the fixed state . The grinder of Claim 9 which has an elastic body which fits the said recessed part and the said convex part in the radial direction of the said spindle .

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